Test of CPT and Lorentz symmetry in entangled neutral kaons with the KLOE experiment

Neutral kaon pairs produced in Ï\u86 decays in anti-symmetric entangled state can be exploited to search for violation of CPT symmetry and Lorentz invariance. We present an analysis of the CP-violating process Ï\u86 â\u86\u92 KSKL â\u86\u92 Ï\u80 +Ï\u80 -Ï\u80 +Ï\u80 - based on 1.7 fb -1 of data collected by the KLOE experiment at the Frascati Ï\u86-factory DAΦNE. The data are used to perform a measurement of the CPT-violating parameters δaμ for neutral kaons in the context of the Standard Model Extension framework. The parameters measured in the reference frame of the fixed stars are:δa0=(-6.0±7.7stat±3.1syst)Ã\u9710-18 GeV,δaX=(0.9±1.5stat±0.6syst)Ã\u9710-18 GeV,δaY=(-2.0±1.5stat±0.5syst)Ã\u9710-18 GeV,δaZ=(3.1±1.7stat±0.5syst)Ã\u9710-18 GeV. These are presently the most precise measurements in the quark sector of the Standard Model Extension. © 2014 The Authors